A national survey of the Oral Health of School Children was conducted during the 1986-87 school year. Approx. 41,000 children were examined by 13 trained and calibrated dental teams. Analysis of DMFS indicated a 37% change in mean estimates compared to a similar study conducted in 1979-80. There was a lower level of disease at every age. Mean DMFS was also lower in all regions of the country; however, there were still regional variations as before. Approx. 50% of the children aged 5-17 were caries free in their permanent dentition. A monograph "Oral Health of U.S. Children, 1986-87" on caries levels was prepared. Analysis of sealant observations was done. Only 7.6% of the children aged 5-17 had sealants present. More females than males had sealants. 11% of the 8-, 9-and 10-year-old children had sealants. The average number of sealants in children with sealants was 4.2 per child. An estimate of the prevalence of dental fluorosis was made using Dean's Index on 2nd through 12th graders. 22% of children showed definite signs of fluorosis, 17% very mild, 4% mild, 1% moderate and 0.3% severe. Regions showed large variations. Analysis of caries attack of primary teeth was done. Mean caries experience for children age 5-9 years was 3.91 dfs. This was a 26% decline from 1979-80 survey. The dfs was lower in every region except Region VII, with the greatest decline observed in Reg. I. Approx. 50% of the children had no dfs; 28% had more than 4 surfaces d or f.